A transfer case with two-gear shifting function

Abstract

This invention relates to a transfer case with a two-speed transmission, comprising a transfer case housing, a first multi-plate clutch, a second multi-plate clutch, a planetary reduction mechanism, an input gear shaft, an output gear shaft, and a lubricating oil pump. The planetary reduction mechanism includes a sun gear, a planet carrier, planetary gears, an external meshing gear, and a ring gear. The first multi-plate clutch is disposed between the transfer case housing and the ring gear and connected to the outer side of the ring gear. The second multi-plate clutch is disposed between the ring gear and the input gear shaft and connected to the inner side of the ring gear. The input gear shaft is connected to the sun gear, the sun gear meshes with multiple planetary gears, the multiple planetary gears mesh with the ring gear, and the external meshing gear meshes with the output gear shaft. This invention features a simple transmission structure, high transmission efficiency, smooth shifting, minimal impact, excellent system lubrication performance, high reliability, a wide shift ratio range, and strong adaptability.

Description

Technical Field

[0001] This invention relates to the field of automotive parts technology, and in particular to a transfer case with a two-speed transmission function. Background Technology

[0002] As one of the most critical components of the powertrain system of all-wheel drive vehicles, the transfer case has a significant impact on the vehicle's power performance. Its main function is to distribute the power output from the engine and transmission to the vehicle's drive system or other power take-off units as needed. Especially for all-wheel drive special vehicles, transfer cases with multi-speed transmissions have better adaptability to road conditions and significantly improve vehicle performance.

[0003] Most existing multi-speed transfer cases employ multi-stage parallel shaft reduction mechanisms, using mechanical shifting structures on each gear shaft to output different speed ratios and torques. While this type of structure can generally meet the functional requirements of all-wheel-drive special vehicles, its overall structure is relatively complex, its transmission efficiency is low, and it struggles to meet the demands of modern vehicle technology. Mechanical shifting mechanisms, in particular, suffer from significant shift shock, low shift success rate, high mechanical system wear, relatively poor reliability, and a relatively short overall service life. Therefore, considering how to reduce shift shock in multi-speed transfer cases, decrease transmission system wear, reduce transmission system complexity, and improve the compactness of the transfer case structure is crucial for the widespread application of multi-speed transfer cases in the all-wheel-drive special vehicle sector. Summary of the Invention

[0004] The purpose of this invention is to provide a transfer case with two-speed transmission function, which uses two sets of multi-plate clutches in conjunction with a planetary reduction mechanism to realize the high and low speed transmission ratio switching of the transfer case, so as to solve the problems of complex structure, low transmission efficiency, large shifting impact and poor reliability of conventional parallel shaft shifting mechanisms.

[0005] This invention is achieved using the following technical solution:

[0006] A transfer case with two-speed transmission includes a transfer case housing and a first multi-plate clutch, a second multi-plate clutch, a planetary reduction mechanism, an input gear shaft, an output gear shaft, and a lubricating oil pump disposed inside the transfer case housing.

[0007] The planetary reduction mechanism includes a sun gear, a planet carrier, a gear ring, planetary gears mounted on the planet carrier, and an external meshing gear.

[0008] The first multi-plate clutch is disposed between the transfer case housing and the gear ring, and is connected to the outer side of the gear ring; the second multi-plate clutch is disposed between the gear ring and the input gear shaft, and is connected to the inner side of the gear ring; the input gear shaft is connected to the sun gear, the sun gear meshes with multiple planetary gears, the multiple planetary gears mesh with the gear ring, and the external meshing gear meshes with the output gear shaft.

[0009] As a further explanation of the invention, the transfer case housing is provided with a first actuating piston, a second actuating piston, a sealing ring, and a third actuating piston.

[0010] A first oil chamber is formed between the first actuating piston and the third actuating piston, a second oil chamber is formed between the first actuating piston and the second actuating piston, and a third oil chamber is formed between the second actuating piston and the sealing ring;

[0011] A first washer ring is provided between the first multi-plate clutch and the first actuating piston; a second washer ring is provided between the second multi-plate clutch and the third actuating piston.

[0012] As a further explanation of the invention, the transfer case housing is also provided with a pressure spring, an axial movement bracket, a thrust bearing, a first disc spring, a disc spring seat, and a second disc spring.

[0013] The transfer case housing is provided with a disc spring seat, and a first disc spring and a second disc spring are respectively provided to cooperate with the first actuating piston and the third actuating piston.

[0014] The input gear shaft is respectively equipped with a pressure spring, an axial moving bracket, and a thrust bearing; the thrust bearing is located between the third actuating piston and the axial moving bracket, and the pressure spring is located between the axial moving bracket and the input gear shaft;

[0015] The second washer is disposed between the axially movable bracket and the second multi-plate clutch.

[0016] As a further explanation of the invention, the transfer case housing is provided with a first hydraulic oil inlet, a second hydraulic oil inlet, and a third hydraulic oil inlet, which are respectively connected to the first oil chamber, the second oil chamber, and the third oil chamber.

[0017] As a further explanation of the invention, the input gear shaft includes an internal connecting spline, a central oil passage, a multi-grind plate connecting and mounting shaft, a clutch lubrication oil passage, a sun gear shaft, and a planetary carrier positioning shaft;

[0018] The lubricating oil pump is mounted on the input gear shaft, the central oil passage is located inside the input gear shaft and communicates with the lubricating oil passages of multiple clutches respectively; the second multi-grip clutch is mounted on the multi-grip connecting and mounting shaft, and the sun gear is mounted on the sun gear shaft.

[0019] As a further explanation of the invention, the planetary carrier includes an external meshing gear, a planetary gear shaft, a central shaft bore, and a planetary gear shaft lubrication passage;

[0020] The planetary carrier positioning shaft passes through the central shaft hole, and a plurality of planetary gear shaft lubrication channels are provided between the central shaft hole and the planetary gear shaft. The planetary gears are mounted on the planetary gear shafts, and a rolling assembly is provided between the planetary gears and the planetary gear shafts.

[0021] As a further explanation of the invention, the gear ring includes an internal gear ring lubricating oil hole, an external spline, an internal spline, internal and external spline lubricating oil holes, and an internal gear ring.

[0022] The first multi-blade clutch is connected to the external spline, the second multi-blade clutch is connected to the internal spline, and the planetary gear is meshed with the internal gear ring.

[0023] The internal gear ring is provided with multiple internal gear ring lubricating oil holes, and the external spline and internal spline are provided with multiple internal and external spline lubricating oil holes.

[0024] As a further explanation of the invention, the hydraulic push stroke of the second actuating piston is greater than the sum of the axial clearance between the first and second actuating pistons and the axial clearance between the first and third actuating pistons.

[0025] As a further explanation of the invention, the axially movable support and the gear ring are in a hole-shaft clearance fit.

[0026] The present invention has the following beneficial technical effects:

[0027] 1. Simple transmission structure and high transmission efficiency: The high and low speed gears of the transfer case can be switched by using two sets of multi-plate clutches in conjunction with the planetary reduction mechanism. Compared with the mechanical shift fork shifting combined with the parallel shaft reduction mechanism, the structure is greatly simplified, the traditional losses are significantly reduced, and the overall size and structural advantages are also significantly improved.

[0028] 2. Smooth shifting with minimal impact: An external hydraulic system is used in conjunction with two sets of multi-grip clutches. High hydraulic pressure drives the friction plates in the multi-grip clutches to contact or disengage, thereby controlling the deceleration or non-deceleration conditions of the planetary reduction mechanism and achieving smooth switching between high and low speed conditions of the transfer case.

[0029] 3. Excellent lubrication performance and high reliability of the system: The system adopts a lubricating oil pump and sets a through-type central oil passage in the center of the input gear shaft, and sets branch lubricating oil passages at the contact movement of the multi-plate clutch and the movement position of the rolling components, so as to achieve good lubrication and cooling between the moving parts and the friction parts, thereby significantly improving the overall reliability of the transfer case transmission system.

[0030] 4. Wide range of shift ratios and strong adaptability: Compared with conventional parallel shaft reduction mechanisms, planetary reduction structures have a larger transmission ratio under the premise of the same volume, which makes the transmission ratio difference between high and low speed gears of the transfer case greater and covers a wider range, thus promoting its adaptability to a wider range of working conditions. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the transfer case structure with two-speed transmission function of the present invention;

[0033] Figure 2 This is one of the schematic diagrams of the transfer case transmission structure with two-speed shifting function of the present invention;

[0034] Figure 3 This is the second schematic diagram of the transfer case transmission structure with two-speed shifting function of the present invention;

[0035] Figure 4 This is a schematic diagram of the gear ring structure of a transfer case with two-speed transmission function according to the present invention.

[0036] Figure 5 This is one of the schematic diagrams of the planetary carrier structure of the transfer case with two-speed transmission function according to the present invention;

[0037] Figure 6 This is the second schematic diagram of the planetary carrier structure of the transfer case with two-speed transmission function of the present invention;

[0038] Figure 7 This is a schematic diagram of the input gear shaft structure of the transfer case with two-speed shifting function according to the present invention.

[0039] In the diagram: 1. Transfer case housing; 2. First hydraulic oil inlet; 3. Second hydraulic oil inlet; 4. Third hydraulic oil inlet; 5. First actuating piston; 6. Second actuating piston; 7. Sealing ring; 8. First washer ring; 9. First multi-plate clutch; 10. Gear ring; 11. Planetary gear; 12. Rolling assembly; 13. Planetary carrier; 14. Lubricating oil pump; 15. Output gear shaft; 16. Input gear shaft; 17. Second multi-plate clutch; 18. Second washer ring; 19. Pressure spring; 20. Axial movement bracket; 21. Thrust bearing; 22. First disc spring; 23. Third actuating piston; 24. Disc spring seat; 25. Second disc spring;

[0040] 101. Lubricating oil hole of internal gear ring; 102. External spline; 103. Internal spline; 104. Lubricating oil holes of internal and external splines; 105. Internal gear ring;

[0041] 131. External meshing gear; 132. Planetary gear shaft; 133. Central shaft bore; 134. Lubrication passage of planetary gear shaft;

[0042] 161. Internal connecting spline; 162. Central oil passage; 163. Multi-grind plate connecting and mounting shaft; 164. Clutch lubrication oil passage; 165. Sun gear shaft; 166. Planetary carrier positioning shaft;

[0043] 201, First oil chamber; 301, Second oil chamber; 401, Third oil chamber. Detailed Implementation

[0044] The present invention will be further described and illustrated below with reference to specific embodiments and the accompanying drawings:

[0045] like Figure 1-7 As shown, a transfer case with two-speed transmission includes a transfer case housing 1 and a first multi-plate clutch 9, a second multi-plate clutch 17, a planetary reduction mechanism, an input gear shaft 16, an output gear shaft 15, and a lubricating oil pump 14 disposed inside the transfer case housing 1.

[0046] The planetary reduction mechanism includes a sun gear, a planet carrier 13, a ring gear 10, a planet gear 11 mounted on the planet carrier 13, and an external meshing gear 131.

[0047] The first multi-plate clutch 9 is disposed between the transfer case housing 1 and the gear ring 10, and is connected to the outer side of the gear ring 10; the second multi-plate clutch 17 is disposed between the gear ring 10 and the input gear shaft 16, and is connected to the inner side of the gear ring 10; the input gear shaft 16 is connected to the sun gear, the sun gear meshes with multiple planetary gears 11, the multiple planetary gears 11 mesh with the gear ring 10, and the external meshing gear 131 meshes with the output gear shaft 15.

[0048] like Figure 3 As shown, the transfer case housing 1 is equipped with a first actuating piston 5, a second actuating piston 6, a sealing ring 7, and a third actuating piston 23.

[0049] The first actuating piston 5 and the third actuating piston 23 are tightly fitted together to form a first oil chamber 201, the first actuating piston 5 and the second actuating piston 6 are tightly fitted together to form a second oil chamber 301, and the second actuating piston 6 and the sealing ring 7 are tightly fitted together to form a third oil chamber 401; furthermore, the hydraulic push stroke of the second actuating piston 6 is greater than the sum of the axial clearance between the first actuating piston 5 and the second actuating piston 6 and the axial clearance between the first actuating piston 5 and the third actuating piston 23;

[0050] A first washer 8 is provided between the first multi-plate clutch 9 and the first actuating piston 5; a second washer 18 is provided between the second multi-plate clutch 17 and the third actuating piston 23.

[0051] like Figure 3 As shown, the transfer case housing 1 is also equipped with a pressure spring 19, an axial movement bracket 20, a thrust bearing 21, a first disc spring 22, a disc spring seat 24, and a second disc spring 25.

[0052] A disc spring seat 24 is provided on the transfer case housing 1, and a first disc spring 22 and a second disc spring 25 are respectively provided between the first actuating piston 5 and the third actuating piston 23;

[0053] A pressure spring 19, an axial moving bracket 20, and a thrust bearing 21 are respectively provided on the input gear shaft 16. The thrust bearing 21 is located between the third actuating piston 23 and the axial moving bracket 20, and the pressure spring 19 is located between the axial moving bracket 20 and the input gear shaft 16. The axial moving bracket 20 and the gear ring 10 are in a hole-shaft clearance fit, and the axial moving bracket 20 can move unidirectionally under the push of the third actuating piston 23. The axial elastic force generated by the pressure spring 19 applies an axial force to the axial moving bracket 20 to ensure that the axial moving bracket 20 and the third actuating piston 23 are always in close contact with the thrust bearing 21. Preferably, the elastic force generated by the pressure spring 19 is much smaller than the elastic force generated by the first disc spring 22.

[0054] The second washer 18 is disposed between the axial moving bracket 20 and the second multi-plate clutch 17.

[0055] like Figure 1 As shown, the transfer case housing 1 is provided with a first hydraulic oil inlet 2, a second hydraulic oil inlet 3 and a third hydraulic oil inlet 4, which are respectively connected to the first oil chamber 201, the second oil chamber 301 and the third oil chamber 401; thus satisfying the high-pressure hydraulic oil delivery.

[0056] like Figure 7 As shown, the input gear shaft 16 includes an inner connecting spline 161, a central oil passage 162, a multi-grind plate connecting and mounting shaft 163, a clutch lubrication oil passage 164, a sun gear shaft 165, and a planetary carrier positioning shaft 166.

[0057] The lubricating oil pump 14 is mounted on the input gear shaft 16, and the central oil passage 162 is located inside the input gear shaft 16 and communicates with the lubricating oil passages 164 of the multiple clutches respectively; the second multi-grip clutch 17 is mounted on the multi-grip connecting and mounting shaft 163, and the sun gear is mounted on the sun gear shaft 165; the lubricating oil pump 14 accurately pumps the lubricating oil to the required parts through the central oil passage 162.

[0058] like Figure 5 , 6 As shown, the planetary carrier 13 includes an external meshing gear 131, a planetary gear shaft 132, a central shaft hole 133, and a planetary gear shaft lubrication passage 134.

[0059] The planetary carrier positioning shaft 166 passes through the central shaft hole 133. Multiple planetary gear shaft lubrication channels 134 are arranged between the central shaft hole 133 and the planetary gear shaft 132. The planetary gear 11 is arranged on the planetary gear shaft 132. A rolling assembly 12 is arranged between the planetary gear 11 and the planetary gear shaft 132. The planetary gear shaft lubrication channels 134 facilitate the accurate delivery of lubricating oil to the planetary gear shaft 132.

[0060] like Figure 4 As shown, the gear ring 10 includes an internal gear ring lubrication oil hole 101, an external spline 102, an internal spline 103, internal and external spline lubrication oil holes 104, and an internal gear ring 105.

[0061] The first multi-blade clutch 9 is connected to the external spline 102, the second multi-blade clutch 17 is connected to the internal spline 103, and the planetary gear 11 is meshed with the internal gear ring 105.

[0062] Multiple internal gear ring lubrication holes 101 are provided through the internal gear ring 105, and multiple internal and external spline lubrication holes 104 are provided through the external spline 102 and internal spline 103 to meet lubrication requirements.

[0063] The transfer case shifting principle of this invention:

[0064] No power input, short-distance manual vehicle movement condition: At this time, the whole vehicle has no power source. High-pressure grease or lubricating oil must be injected into the third hydraulic oil inlet 4, that is, the third oil chamber 401 is filled with high pressure, thereby pushing the second actuating piston 6 to move to the left, so as to push the first actuating piston 5 and the third actuating piston 23 away from the first multi-plate clutch 9 and the second multi-plate clutch 17, so that the first multi-plate clutch 9 and the second multi-plate clutch 17 are both in the power disengagement state, thereby realizing the release of the transfer case brake, so that the vehicle can be manually pushed for short-distance movement;

[0065] Low-speed operation: High-pressure hydraulic oil is injected into the first oil chamber 201 through the second hydraulic oil inlet 3, pushing the first actuating piston 5 to move to the right. Axial pressure is applied to the first washer ring 8 to push the friction plates between the first multi-plate clutch 9 into close contact, that is, to connect and fix the gear ring 10 to the transfer case housing 1. At the same time, under the action of high-pressure hydraulic oil, the third actuating piston 23 is pushed to move to the left, thereby releasing the axial pressure of the axial moving bracket 20 on the second washer ring 18 under the action of the pressure spring 19. That is, the second multi-plate clutch 17 loses its locking function, thereby realizing the disconnection of power between the input gear shaft 16 and the gear ring 10. At this time, the planetary reduction mechanism can perform a deceleration action. The power input from the input gear shaft 16 will first be decelerated through the planetary reduction mechanism, and then the external meshing gear 131 on the planet carrier 13 will mesh with the output gear shaft 15, and the output gear shaft 15 will output the power.

[0066] High-speed operation: High-pressure hydraulic oil is injected into the second oil chamber 301 through the third hydraulic oil inlet 4, pushing the first actuating piston 5 to move to the left. At this time, the first washer ring 8 is not subjected to any axial pressure, thereby releasing the locking function of the first multi-plate clutch 9. There is no connection between the gear ring 10 and the transfer case housing 1. At the same time, under the action of the first disc spring 22, the third actuating piston 23 moves to the right. Through the transmission of the thrust bearing 21, the axial moving bracket 20 also moves to the right, thereby applying a certain axial force to the second washer ring 18. The second washer ring 18 presses the friction plates of the second multi-plate clutch 17, making them in close contact, that is, connecting and fixing the input gear shaft 16 and the gear ring 10. Thus, the speed of the sun gear shaft 165 of the planetary reduction mechanism is the same as the speed of the gear ring 10, that is, the reduction ratio of the planetary reduction mechanism is 1. At this time, the power input by the input gear shaft 16 will be directly transmitted through the meshing of the external meshing gear 131 on the planetary carrier 13 and the output gear shaft 15, and the power will be output by the output gear shaft 15.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A transfer case with two-speed transmission, characterized in that, It includes a transfer case housing (1) and a first multi-plate clutch (9), a second multi-plate clutch (17), a planetary reduction mechanism, an input gear shaft (16), an output gear shaft (15), and a lubricating oil pump (14) disposed inside the transfer case housing (1); The planetary reduction mechanism includes a sun gear, a planet carrier (13), a gear ring (10), a planet gear (11) mounted on the planet carrier (13), and an external meshing gear (131). The first multi-plate clutch (9) is disposed between the transfer case housing (1) and the gear ring (10) and is connected to the outside of the gear ring (10); the second multi-plate clutch (17) is disposed between the gear ring (10) and the input gear shaft (16) and is connected to the inside of the gear ring (10); the input gear shaft (16) is connected to the sun gear, the sun gear is meshed with multiple planetary gears (11), the multiple planetary gears (11) are meshed with the gear ring (10), and the external meshing gear (131) is meshed with the output gear shaft (15); The transfer case housing (1) is provided with a first actuating piston (5), a second actuating piston (6), a sealing ring (7), and a third actuating piston (23); A first oil chamber (201) is formed between the first actuating piston (5) and the third actuating piston (23), a second oil chamber (301) is formed between the first actuating piston (5) and the second actuating piston (6), and a third oil chamber (401) is formed between the second actuating piston (6) and the sealing ring (7). A first washer ring (8) is provided between the first multi-plate clutch (9) and the first actuating piston (5); a second washer ring (18) is provided between the second multi-plate clutch (17) and the third actuating piston (23); The transfer case housing (1) is also equipped with a pressure spring (19), an axial movement bracket (20), a thrust bearing (21), a first disc spring (22), a disc spring seat (24), and a second disc spring (25); The transfer case housing (1) is provided with a disc spring seat (24), and a first disc spring (22) and a second disc spring (25) are respectively provided in cooperation with the first actuating piston (5) and the third actuating piston (23); the input gear shaft (16) is respectively provided with a pressure spring (19), an axial movement bracket (20), and a thrust bearing (21); The thrust bearing (21) is disposed between the third actuating piston (23) and the axial moving bracket (20), and the pressure spring (19) is disposed between the axial moving bracket (20) and the input gear shaft (16); The second washer (18) is disposed between the axial moving bracket (20) and the second multi-plate clutch (17); The input gear shaft (16) includes an internal connecting spline (161), a central oil passage (162), a multi-grind plate connecting and mounting shaft (163), a clutch lubrication oil passage (164), a sun gear shaft (165), and a planetary carrier positioning shaft (166). The lubricating oil pump (14) is mounted on the input gear shaft (16), the central oil passage (162) is located inside the input gear shaft (16) and is connected to the lubricating oil passages (164) of the multiple clutches respectively; the second multi-grip clutch (17) is mounted on the multi-grip connecting and mounting shaft (163), and the sun gear is mounted on the sun gear shaft (165).

2. The transfer case with two-speed transmission function as described in claim 1, characterized in that, The transfer case housing (1) is provided with a first hydraulic oil inlet (2), a second hydraulic oil inlet (3) and a third hydraulic oil inlet (4) on its exterior, and these inlet and outlet are respectively connected to the first oil chamber (201), the second oil chamber (301) and the third oil chamber (401).

3. The transfer case with two-speed transmission function as described in claim 1, characterized in that, The planetary carrier (13) includes an external meshing gear (131), a planetary gear shaft (132), a central shaft hole (133), and a planetary gear shaft lubrication passage (134); The planetary carrier positioning shaft (166) passes through the central shaft hole (133), and a plurality of planetary gear shaft lubrication channels (134) are arranged between the central shaft hole (133) and the planetary gear shaft (132). The planetary gear (11) is arranged on the planetary gear shaft (132), and a rolling assembly (12) is arranged between the planetary gear (11) and the planetary gear shaft (132).

4. The transfer case with two-speed transmission function as described in claim 3, characterized in that, The gear ring (10) includes an internal gear ring lubrication oil hole (101), an external spline (102), an internal spline (103), internal and external spline lubrication oil holes (104), and an internal gear ring (105); The first multi-blade clutch (9) is connected to the external spline (102), the second multi-blade clutch (17) is connected to the internal spline (103), and the planetary gear (11) is meshed with the internal gear ring (105). The internal gear ring (105) is provided with a plurality of internal gear ring lubricating oil holes (101), and the external spline (102) and internal spline (103) are provided with a plurality of internal and external spline lubricating oil holes (104).

5. The transfer case with two-speed transmission function as described in claim 4, characterized in that, The hydraulic push stroke of the second actuating piston (6) is greater than the sum of the axial clearance between the first actuating piston (5) and the second actuating piston (6) and the axial clearance between the first actuating piston (5) and the third actuating piston (23).

6. The transfer case with two-speed transmission function as described in claim 5, characterized in that, The axial moving bracket (20) and the gear ring (10) are in a hole-shaft clearance fit.

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